/**
 * 题目链接：
 * 完成时间：2025/11/12 09:06
 * 简要思路：
 */
#include <bits/stdc++.h>
#define range(i, b, e) for (auto i(b); i != (e); i++)
#define rep(i, b, e) for (auto i(b); i <= (e); i++)
#define req(i, b, e) for (auto i(b); i >= (e); i--)
using namespace std;
typedef long long LL;
typedef pair<int, int> Pii;

const int N = 2e5, M = 200, mod = 998244353;
int n, m, k, q;
LL dp[N+5][M+5];

int main() {
	freopen("sequence.in", "r", stdin);
	freopen("sequence.out", "w", stdout);
	ios::sync_with_stdio(false);
	cin.tie(nullptr); cout.tie(nullptr);
	cin >> n >> m >> q >> k;
	if (q < m) {
		cout << 0;
		return 0;
	}
	dp[0][0] = 1;
	rep(i, 1, q) rep(j, 0, m) {
		LL del = LL(n - m + j) * k % mod;
		dp[i][j] = (dp[i-1][j-1] * j + dp[i-1][j] * del) % mod;
	}
	cout << dp[q][m] * (n-m+1) % mod;
	return 0;
}
